Pouches are commonly utilized in the foodservice area and in clinical nutrition to conveniently deliver viscous food such as sauce or non-viscous liquid food such as ready-to-use beverages. Such products may be dispensed at ambient, hot or chilled conditions depending upon the nature and applications of the product. In most cases, it is important to maintain a high degree of hygiene in the dispenser to avoid bacterial contamination and growth hazards when dispensing. It is also important to provide a pouch that can be associated with the dispenser in a quick and convenient manner. Therefore, pouches have been produced with sealingly attached peripheral members. For instance, peripheral members may be fitments, or accessories for holding or aiding members that are sealed to the pouch in order to establish a convenient and rapid fluid connection with a hose or similar that enables to deliver the product out of the pouch. The location of the fitment on the pouch may also be an important factor that ensures convenient loading and emptying of the pouch with as less as residual product as possible within the pouch.
Pouches are usually preformed into bags prior to the time of filling and have these dispensing fitments sealed to a single sheet of the film prior to the film being formed and sealed into a bag. The fitment may be attached by being inserted through a hole that is punched in the web of film and then sealed to the film. The product is then filled through the fitment and sealed with a cap. These methods lack flexibility since the position of the fitment is determined at the time the bag is formed. Furthermore, the closure with a mere cap is not satisfactory on an hygienic standpoint and the operation for placing a new bag in the food dispenser may be messy and inconvenient for the operator.
There are other sorts of form-fill-seal systems (F/F/S) as described in U.S. Pat. No. 3,894,381 to Christine et al. wherein the bag is formed in tubular configuration in an automated wrapping machine, the fitment is attached on a side of the bag in the machine, the product is filled inline along an open end and, finally the pouch is closed by sealing along its filling end.
These systems present several shortcomings. A first disadvantage is that the filling machine needs to integrate a fitment sealing station. Therefore, not every filling machine is suitable for producing a fitmented pouch and the capital expenditures is elevated to equip a factory in suitable F/F/S lines capable of handling such pouches. A second disadvantage comes from the lack of flexibility regarding the sealing position of the fitment on the pouch and/or the type and dimensions of fitment used which cannot be easily modified since the sealing operation is closely related to the filling machine. This lack of flexibility increases the overall cost of the product and manufacturing complexity.
Another drawback of the previous technique is for the food pouches that contain a microbiologically sensitive food substance such as low acid food. Those pouches may require to be heat treated after filling of the food product within the pouches. This retorting process is widely used for food cans but is not common for the flexible containers with dispensing fitments attached. If retorting is carried while the fitment is already sealed to the pouch, it may affect the integrity of the seal and/or diminish its strength. Furthermore, it may logistically interfere with loading and unloading of the retorts as well as the loading pattern and pouch density within the retort.
Therefore, there would be a need for a method that can handle attachment of a fitment to a pouch after the product has been filled in the pouch and the pouch sealed to form a filled-sealed pouch. There would also be a need for a pouch to be retorted before the fitment has been sealed to it.
U.S. Pat. No. 4,718,215 to Carveth et al. relates to an apparatus for attaching fitments to filled flexible containers that includes a coating wheel for coating a surface of the fitments with a hot melt adhesive or slurry and a continuous conveyor for delivering the fitments in juxtaposition to the flexible containers and urging the fitments against the containers. The sealing energy is provided by high frequency induction welding and the slurry comprises finely ground energy absorbing material such as ferrous iron, nickel, cobalt and the like. Conveyor belts are further provided on each side of the container to limit lateral movement of the container during welding. Such an apparatus is relatively complicated and requires handling of viscous adhesive and special welding and conveying equipment. Furthermore, the apparatus lacks flexibility as it would be difficult to change the position of the fitment on the container because of the relatively fixed conveying arrangement.
U.S. Pat. No. 2,850,422 to Welch is an even older method that also uses high frequency to attach a port structure to a fluid container. The method uses a first metallic electrode to the port element and a second substantially larger electrode to an imperforate area of the other wall of the container opposite the volume of liquid. This method may pose electric hazards and is very dependent on the liquid capacitor which may render it difficult or slow to use at an industrial scale regarding certain food products.
U.S. Pat. No. 3,231,444 to Shick relates to a method of heat sealing the plane surface of a thermoplastic fitment to a planar sheet of thermoplastic material wherein the fitment comprises an upstanding rib of cross-sectional area less than the plane surface and wherein the rib is heated to place it in a molten condition and pressed onto the sheet of thermoplastic. This method requires high heating energy and is slow to obtain a bond of sufficient strength with the risk of puncturing the sheet of material.
U.S. Pat. No. 6,205,746 to Moss et al. relates to a post-processing fitment applicator for applying a fitment to a formed, filled and sealed carton that is used in conjunction with a linear form, fill seal packaging machine such as TETRA REX® packaging machines. The applicator uses a hot melt source to coat the fitment sealing surface. This apparatus is more adapted for sealing fitments onto substantially rigid containers.
EP Patent application 1 167 211 A1 relates to an assembly with a pouch and a fitment which is applied to the pouch by ultrasonic sealing wherein the pouch is made with a film material specially treated on the inside surface through the addition of a special lacquer or film layer to avoid a sealing at this position or wherein the fitment consists of any thermoplastic or a special blended polymer like metallocene. Sealing is carried out by vibrating at high frequency a sonotrode supporting the fitment to generate a frictional heat build-up at the seal interface with the pouch.
In other instances, it may be useful to attach two or more pouches together to form a sealed pouch assembly so as to increase the delivery capacity of the assembly without producing a larger pouch. Indeed, although F/F/S machines may be configured to form pouches of various sizes, there are typically limits to the sizes available. If a commercial application calls for the delivery of pouches of higher capacity, it may be advantageous to be able to produce pouches that can be sealed together so as to reach the desired capacity.
Furthermore, there are a number of different packaging machine manufacturers in the packaging industry. They manufacture machines and pouches of various sizes and configurations to meet the demands of various groups and applications. It is currently impossible to take advantage of a wide range of machines available in the industry without going through expensive modifications to adapt the sealing methodology and features to the machines. This greatly limits the economic expansion of the food pouch manufacturing base.
Therefore, a need exists for a method for post-attachment of a peripheral member to a filled-sealed pouch that is, in particular, flexible, economic and reliable. These needs are now met by the present invention.